Signal amplitude responsive trigger circuits for quantizing



Nov. L 1949.

D. CUNNEEGHAM SIGNAL AMPLITUDE RESPONSIVE TRIGGER CRCUITS FOR QUNTIZING Filed Sept. l2, 1945 Patented Nov. 1, 1949 SIGNAL AMPLITUDE RESPONSIVE TRIGGER CIRCUITS FOR QUANTIZING Rhean D. Cunningham, Arlington County, Va. Application September l2, 1945, Serial No. 616,482

(Cl. Z50-27) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) 4 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention is in electrical apparatus and particularly is a novel quantizing circuit.

The principal object of this invention is to provide a novel circuit which will sample a iiuctuating direct current voltage at intervals and provide an output on one of a plurality of lines, the selection of the line being dependent upon the value of the input signal at the instant of sampling.

Other objects will be apparent from a reading of the following specification and claims.

The single drawing is a schematic wiring diagram of the quantizing -circuit of my invention.

The circuit comprises six triode tubes ICI-I I, I2I3', and III-I5 direct-coupled together in pairs in Eccles-Jordan fashion. An output lead I is connected to theplates of tubes IB and I4 through decoupling resistors 25 and 25 and to ground through resistor 2E.

Output leads I'I through 2| are provided for tubes I through I5, each output serving two tubes in a fashion similar to that just described for Vtubes Ill and I4.

It should be understood that the circuit herein shown and to be described is intended to sense only six different levels in an input signal.

Should it ,be desired to sense more than six levels, more tubes will be used, but the principles of construction and operation will be identical.

When triodes II'I and I4 are in a conducting condition, the voltage developed across resistor 2S is at its minimum value. When either I0 or I4 is conducting but not both tubes, an intermediate voltage value is developed across resistor 26. When neither of the said triodes is conducting, a maximum voltage for the circuit is developed across the indicated resistor, and the desired signal appears on output lead IE.

The circuit is intended to be exposed to the input voltage for a short period of time only by closing switch 30 in line 3l. In practicemanu ally operable switch 39 will ordinarily be replaced by a mechanical or electronic switch, but no such switch forms a part of this invention.

With the circuit in Zero or initial condition and also when the input voltage represents the first step level value of the six possible values, triodes II, I3, and I5 are conducting, and triodes I 0, I2, and I4 are thus cut off as a result of the Eccles- Jordan coupling. The grids of triodes I 0, I2, and

2 I4 are biased increasingly negative by means of variable resistors 35, 36, and 3l so that a larger positive input voltage is required to lire tube I2 than tube I0, and a larger positive input voltage still is required to iire tube I4.

The absolute values of grid resistance for tubes I0, I2, and I4 are determined by the sizes of the steps to be indicated on the output line.

As mentioned, when the input signal value is at the i'lrst step level, triodes II, E3, and I5 are conducting. Under these conditions, neither triode I0 nor triode I4 conducts, and, since both are connected to output line I6, a maximum value output appears on this line. No other output line connects with more than one nonconducting triode.

Should the input signal rise to the second step level value, the bias on tube I I) is reduced to such a point as to produce conduction therein, and tube II is extinguished. For this condition, output lead Il alone carries a maximum value signal since neither triode II nor I2, both of which are connected to the said output, is conducting, whereas at least one tube on every other output line is in a conducting condition. As the input voltage reaches the third step level, triode I2, as well as triode I0, is caused to conduct, and triodes II and I3 are thereby cut off so that the output line associated with tubes I3 and I4, namely line I8, carries a maximum signal. An input signal of the next highest value will produce conduction in triodes I0, I2, and I4, and thereby cut off triodes II, I3, and I5. Output line I9, associated with triodes II and I5, now carries a maximum signal.

When the input signal value rises to another level, as the fifth, triode I4 continues to conduct, and a negative biasing voltage is coupled back to triodes I0 andIZ, through resistors 4I! and 4I, respectively. This bias voltage is not large enough to cut 01T either of the last mentioned tubes at the fourth step level of input voltage, but, with an increase in the input, triode I0 is unable to hold tube II cut ofi; thereupon triode II conducts and triode I0 is cut 01T so that output line 20, associated with triodes IIJ and I3, carries the maximum output voltage.

At the sixth input level, not only is triode I0 unable to cut oli or to hold cut off triode II, but triode I 2 is likewise unable to prevent conduction in triode I3. Triodes II and I3 thereupon, aided by the biasing voltage coupled back to tubes I0 and I2 from tube I4, hold tubes I0 and I2 cut off, an-d the maximum voltage appears on lead fl, this lead pairing the outputs of tubes l2 and After a predetermined time interval, or whenever desired, the circuit may be restored to its initial condition by applying large positive pulses to tubes Il, I3, and l5 from line 40 to produce conduction therein.

The foregoing description is in specific terms, and many modifications will readily suggest themselves. The invention should not, in other words, be considered as limited to the exact apparatus shown and described, but, instead, for the true scope thereof, reference should be had to the appended claims.

I claim:

1. In a circuit of the nature described including a plurality of output lines, means for selectively energizing said lines according to the amplitude of an input signal comprising a plurality of trigger circuits each having two conditions of electrical stability and each including a rst tube and a second tube all of said tubes having a plate, a cathode, and a grid element, a power supply connected to the plates of said tubes, a source of biasing voltage and means connecting the same to the grid elements of said tubes to condition the said first tubes for conduction at a predetermined input signal level and to condition the sai-d second tubes for conduction at progressively different input signal levels, means for applying an input signal to all of said grid elements in parallel excepting the grid element of one of said first tubes, and means for restoring said circuit to its initial condition after its condition has been altered.

2. In a circuit of the nature described including a plurality of output lines, means for selectively energizing said lines in accordance with the amplitude of an input signal comprising a plurality of trigger circuits each having two conditions of electrical stability and each including a first tube and a second tube all of said tubes having a plate, a cathode, and a grid element, a power supply connected to the plates of said tubes, a source of biasing voltage and means connecting the same to the grid elements of said tubes to condition the first tubes for conduction at a predetermined signal level and to condition the said second tubes for conduction at progressively different input signal levels, means for applying an input signal to al1 of said grid elements in parallel excepting the grid element of one of said rst tubes, connecting means between each of said output lines and a plurality of said tubes no two tubes so connected being within the same trigger circuit, and means for restoring said circuit to its initial condition after its condition has been altered.

3. In a circuit of the nature described including a plurality of output lines, means for selectively energizing said lines in accordance with the amplitude `of an input signal comprising a plurality of trigger circuits each having two conditions of electrical stability and each including a first tube and a second tube all of said tubes having a plate, a cathode, and a grid element, a power supply connected to the plates of said tubes, a source of biasing voltage and means connecting the same to the grid elements of said tubes to condition the said first tubes for conduction at a predetermined input signal level and to condition the said second tubes for conduction at pro-gressively different input signal levels, means for sampling an input signal and applying the instantaneous voltages thereof to all of said grid elements in parallel excepting the grid elements of one of said first tubes, and means for restoring said circuit to its initial condition after its condition has been altered.

4. In a circuit of the nature described, the combination of a first trigger circuit, a second trigger circuit, and a third trigger circuit each of said trigger circuits including two tubes and having two conditions of electrical stability'one tube of each trigger circuit being initially conducting and the other tube of each trigger circuit being initially off the off tubes of said first, second, and third trigger circuits being biased progressively more heavily to prevent conduction therein, a plate voltage supply for said tubes, means for applying a fiuctuable input signal to said tubes excepting the initially conducting tube of the third trigger circuit, an output line connected to the initially off tubes of said first and third trigger circuits, a second output line connected to the initially on tube ofthe first trigger circuit and the initially off tube of the second trigger circuit, a third output line connected to the initially on tube of the second trigger circuit and the initially off tube of the third trigger circuit, a fourth output line connected to the initially on tube of the first trigger circuit and the v initially on tube of the third trigger circuit, a fifth output line connected to the initially off tube of the first trigger circuit and the initially on tube of the second trigger circuit, a sixth output line connected to the initially off tube of the second trigger circuit and the initially on tube of the third trigger circuit, means for coupling back the output of the initially off tube of the third trigger circuit to the inputs of the initially off tubes of the first trigger circuit and the second trigger circuit, and means for extinguishing said initially off tubes.

RHEAN D. CUNNINGHAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Miller et al Dec. 11, 1945 OTHER REFERENCES Number 

